This new technique and the conventional blood culture technique are currently being compared, specimen for specimen, although not all samples are lysed for culture. The present benign lysing solution is non-injurious to most pathogens, and indeed forms a superior growth medium for many. But it contains 0.04% Triton x-100, which adversely affects some pathogens. Tween 20 (polyoxyethylene sorbitan monolaurate) was tested to replace Triton x-100, and was discovered to be non-toxic, even to Neisseria meningitidis, while lysing blood cells adequately, in 2% concentration. Testing should be complete in the next few months.